U.S. Application Ser. No. 953,677 filed Oct. 23, 1978 (now U.S. Pat. No. 4,181,386) discloses and claims a connector clip comprising a one-piece stamped and formed member of spring material, such as spring steel, which is adapted to be mounted on a circuit board in straddling relationship to parallel spaced-apart circuit board conductors. The connecting connector clip has integral cantilever springs which bear against the circuit board and which serve to press the cable against the circuit board so that the cable conductors are resiliently urged against the circuit board conductors. The connector clip does not, therefore, serve an electrical function but merely a mechanical function of pressing the cable conductors against the circuit board conductors.
The above identified application discloses and teaches the use of a separate spring unloading tool which can be used to raise the spring members away from the circuit board so that the cable can be inserted between the circuit board and the spring members under zero insertion force (ZIF) conditions. It has been found that connector clips of this type often require ZIF features for the reason that the forces exerted by the springs are quite high and it is difficult to insert the cable between the springs and the circuit board when the springs are resiliently biased against the circuit board. Application Ser. No. 24,356 filed Mar. 27, 1979, shows another form of zero insertion force connector clip in which an integral lifting member is provided on the ends of the springs.
The present invention is directed at the achievement of an improved ZIF connector clip in which the spring lifting means is assembled to and remains part of the connector clip. The invention is further directed to the achievement of a connector clip which can be produced with a relatively long span so that it can be used for cables and connecting conductors of high count cables (cables having more than ten conductors) to equal numbers of circuit board conductors. It has been found that there is a limit to the number of cable conductors which can be connected to circuit board conductors when connector clips of the type disclosed in the above identified applications are used. The connector clip must straddle all of the circuit board conductors when it is assembled to the circuit board and the stresses imposed on the connector clip by the spring members will become relatively high if the clip is such that it must span a wide array of side-by-side circuit board conductors.
A connector clip in accordance with the present invention comprises a clip bar having flanges extending from its ends and means on the flanges for mounting the clip on a circuit board with the clip bar extending transversely of the circuit board conductors. A plurality of cantilever springs extend from one edge of the clip bar and each spring is reversely bent adjacent to the clip bar thereby to provide a spring arm portion extending obliquely towards the circuit board. Each spring has an arcuate bend which forms a contact portion, which bears against the circuit board, and a free end which extends from the contact portion and is between the flanges of the clip bar. The spring lifting member is mounted in the flanges and has an intermediate lifting portion which extends transversely past the free ends of the spring members and is between the spring members and the surface of the circuit board. This lifting member is supported in slots in the flanges which permit its movement away from the surface of the circuit board and towards the clip bar. Upon such movement of the lifting member, the free ends of the springs are raised from the surface of the circuit board and the contact portions of the springs are also moved away from the surface of the circuit board so that a cable can be inserted between the springs and the circuit board under ZIF conditions. Camming and handle means are provided on the lifting member externally of the flanges to permit lifting of the springs as described above.